fix: get_event_loop - set new loop as current loop in threads (#75)

multicall/utils.py

@@ -59,13 +59,15 @@ def get_async_w3(w3: Web3) -> Web3:
     async_w3s[w3] = async_w3
     return async_w3
 
-def get_event_loop() -> asyncio.AbstractEventLoop:
+def get_event_loop() -> asyncio.BaseEventLoop:
     try:
-        return asyncio.get_event_loop()
+        loop = asyncio.get_event_loop()
     except RuntimeError as e: # Necessary for use with multi-threaded applications.
         if not str(e).startswith("There is no current event loop in thread"):
             raise e
-        return asyncio.new_event_loop()
+        loop = asyncio.new_event_loop()
+        asyncio.set_event_loop(loop)
+    return loop
 
 def await_awaitable(awaitable: Awaitable) -> Any:
     return get_event_loop().run_until_complete(awaitable)